Anti-inflammatory effects of glycyrol isolated from Glycyrrhiza uralensis (Leguminosae) in LPS-induced RAW264.7 macrophages
The anti-inflammatory effects of glycyrol, a benzofuran coumarin, isolated from Glycyrrhizae Radix were studied. Glycyrol of 5, 25 and 50µM dose-dependently inhibited nitric oxide (NO) production by down-regulating inducible nitric oxide synthase (iNOS), and alleviated cyclooxygenase-2 (COX-2) expression, in both mRNA and protein expression levels in LPS-induced RAW264.7 macrophages. Furthermore, glycyrol dose-dependently decreased mRNA of the pro-inflammatory cytokine IL-1β and IL-6. LPS-induced NF-κB activation was prevented in RAW264.7 macrophages by inihibiting phosphorylation and consequent degradation IκBα. In addition, administration of glycyrol (30 and 100mg/kg, i.p) reduced the thickness of the carrageenan-induced mouse-paw edema swelling. Taken together, our results indicate that glycyrol is an important anti-inflammatory constituent of Glycyrrhizae Radix, and its anti-inflammatory effect is attributed to inhibit phosphorylation and consequent degradation of IκBα.
Acknowledgement: This work was supported by a grant from the Korea Food and Drug administration for Studies on the Identification of the Efficacy of Biologically Active Components from Oriental Herbal Medicines (2007).